Modified Allen’s Test Is Not a Reliable Predictor of Forearm Vascular Dominance

초록

Background: The modified Allen’s test(MAT) is a bedside method for evaluating hand circulation before radial forearm free flap harvest. Although widely used, its reliability in predicting forearm vascular dominance is uncertain. This study investigated the correlation between MAT outcomes and arterial diameters on computed tomography angiography(CTA) to assess its clinical value in distal forearm circulation Methods: We retrospectively reviewed patients who underwent radial forearm free flap reconstruction between 2012 and 2023 with available preoperative CTA imaging. Diameters of the radial and ulnar arteries were measured at the distal radioulnar joint, and MAT results were recorded as capillary refill times. Correlation analysis was performed between arterial size and MAT findings. Results: A total of 41 patients included. Across both arms, the radial artery demonstrated significantly larger diameters than the ulnar artery. Nonetheless, MAT flushing time showed no significant correlation with vessel caliber. Four patients demonstrated MAT times exceeding 10 seconds, but these prolonged results were not linked to flap necrosis or loss.